The present invention pertains to stuffing box assemblies, and more specifically, to an improved structure allowing easier access to the adjusting means by which the gland is tightened against the seal between a shaft and housing. The invention is particularly applicable to valve assemblies, wherein the necessity for mounting a valve actuator closely adjacent to the stuffing box makes access to such adjusting means difficult. However, various principles of the invention can also be applied to other types of apparatus, and will be particularly useful in those in which access to the adjusting means for a stuffing box gland is made difficult because of adjacent apparatus.
U.S. Pat. No. 2,711,333 and U.S. Pat. No. 3,223,425 illustrate generally what is probably the most common arrangement for providing adjustment of a packing gland for a stuffing box assembly. As shown in those patents, the gland is provided with a radial flange, and one or more studs mounted in the housing extend through that flange. On the opposite side of the flange from the housing, each stud is provided with an adjustable nut which, when threaded inwardly toward the housing, urges the gland ahead of it thus compressing the seal. U.S. Pat No. 860,035 illustrates a variation for an apparatus in which there are two generally oppositely directed glands arranged such that both of them can be tightened by a common set of studs and adjusting nuts.
One of the primary difficulties in accommodating the general scheme illustrated in U.S. Pat. No. 2,711,333 and U.S. Pat. No. 3,223,425, discussed above, to valve assemblies is that which occurs when a valve actuator must be mounted on the housing closely adjacent the stuffing box. This requires that some portion of the housing, or an appendage thereto extend past the stuffing box and the gland adjusting system while still allowing access to the latter. One approach to this problem is illustrated in U.S. Pat. No. 4,156,520. As shown in this patent, the actuator is not mounted directly on the neck of the valve body or housing, but rather, is mounted on supports spaced laterally outwardly from the valve stem and valve neck, the latter being truncated. This approach has several disadvantages. In the first place, it is expensive in that it requires a greater amount of material and machining thereof to form the actuator support structure, whether it is formed integrally with the valve housing or attached thereto. Furthermore, access to the actuating nuts for adjusting the packing gland is still relatively difficult in that the nuts must be reached through windows formed by the actuator support structure, and in some cases, parts of the actuator and/or other ancillary apparatus may even overhang these windows.
Another approach is illustrated in U.S. Pat. No. 2,587,474. In this structure a sleeve which bears on the upper end of the packing gland to force it downwardly is threaded about the exterior of the neck portion of the housing. This arrangement is also undesirable, particularly in valve assemblies, in that it requires external machining of the neck and a more extensive gland structure, including a bulky sleeve which consumes additional space about the exterior of the neck.